I have to echo the recommendation for a 2 x 72" machine. If you purchase one of the "top end" machines you'll never be sorry. Even if you decide to sell it down the road, you will get nearly your money back out of it. If you go with a 1" machine (either 30 or 42") you're just throwing that money away. You'll out grow the machine very quickly, and will never be able to sell for anything near what you paid for it.....and possibly not at all.
As with most knifemakers, I've been down the road of trying to use an inadequate grinder, thinking that was all I could afford....its nothing by frustration, wasted time, and wasted money. After spending enough money to have purchased a couple of the "top end" machines, I finally purchased a 2 x 72 machine, and wished I'd have just saved my pennies and purchased the "right" tool in the first place.